As the need for transferring large amounts of information, such as data associated with video and audio signals, over wireless communication systems has increased, handover procedures where user equipment moves from a cell to another may introduce a significant decrease in the effective capacity of the system. This is especially the case when the handover occurs between cells with different radio interfaces. The difference between the radio interfaces may be due to different carrier frequencies or different radio access technologies between the cells participating the handover.
The handover may occur in different states of the radio resource control. Such states include a connected state in which the user equipment is allocated a dedicated channel, and an idle state in which the user equipment is not allocated a dedicated connection. Common channels, such as common pilot channels and common broadcast channels, are in turn used in idle states.
In an idle state, the user equipment is capable of carrying out cell change procedures aimed at selecting a cell which the user equipment can camp on after leaving the serving cell. The cell change procedures are controlled by the network using control information for the cell change procedures. The control information associated with the cell change in an idle state is broadcast to the user equipment via control channels of the radio system.
According to prior art solutions, the control information associated with the cell change procedures is typically based on field measurements, and the control information is fed in the system during the network set-up. The prior art solutions can lead to a situation, where the user equipment camps on a cell with a limited optimisation level, thus increasing the probability for handover during a dedicated connection and data transfer. As a result, the capacity of the radio system is decreased due to simultaneous signalling and data transfer.